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Posted: Sun Apr 18, 2010 11:59 pm
by jackssmirkingrevenge
Dave_424 wrote:Im not really sure what to do, I doubt I will get the power that I want from the size of cartridge Im planning on using. (around the .50 BMG size)
With a
coaxial design with 0.303 dimensions power wasn't too impressive even at 800 psi, a pneumatic has its limitations when you're constraining the size.
I'm
playing aroundwith hybrid cartidges at the moment, instead of a piston you might want to consider simply retaining your projectile by friction in a seal, champagne cork style, it's not an exact science but makes for an incredibly simple cartridge, in my case the BB can certainly be retained for a 10x mix.
Posted: Mon Apr 19, 2010 4:14 am
by zomgwtfbbq
Dave_424 wrote:Im not really sure what to do, I doubt I will get the power that I want from the size of cartridge Im planning on using. (around the .50 BMG size)
So my thoughts have turned to a high mix hybrid. Using the shape of a firearm cartridge, could I use some kind of piston?
EDIT: Modelling roughly the same size cartridge as a .50 I can roughly get a 100 grain bullet at 800+ fps for about 140 foot pounds.
However if Im going hybrid, should i just say screw it and go big?
Dave
I'm already working on that. Yes. 50 calibre, semi-auto, cartridge-fed, blow-back.
For something bigger than 50 calibre (with burst disk), you could check this out
http://www.spudfiles.com/forums/hybrid- ... 20147.html
Posted: Mon Apr 19, 2010 9:13 am
by POLAND_SPUD
@Dave_424
remember that you can always use higher mix...
I am not very experienced when it comes to hybrids (but I am planing to build one) but AFAIK low volume at high mix is more efficient than large volume at low mix